39 The true greatness of this jubilee year is in the humble answer of the man who admits that he is a sinner. Great blessings for the Church could be justly anticipated if every pilgrim to Lourdes - in fact, every Christian united in spirit with the centenary celebrations - would first realize within himself this work of sanctification, "not in word, neither with the tongue, but in deed and in truth." Moreover, everything invites him to this work, for nowhere, perhaps, except at Lourdes does one feel so moved to prayer, to the forgetting of oneself, and to charity.
Source: Le Pelerinage de Lourdes (Vatican.va)